biology

Question 1

Allele

Answer 1

Different versions of a gene; alleles are genes that occupy the same position on homologous chromosomes

Question 2

Asexual Reproduction

Answer 2

Reproduction only involving one parent producing identical offspring

Question 3

Bases

Answer 3

Adenine, Guanine, Cytosine, Thymine

Question 4

Carrier

Answer 4

Has inherited a genetic trait or mutation, but who does not display the trait, but can pass it on to their offspring

Question 5

Characteristic

Answer 5

(also known as a trait), an attribute of an individual e.g tall plant, brown hair, blue eyes

Question 6

Chromosome

Answer 6

Strand of DNA which contains many genes; a normal human cell has 46 (23 pairs)

Question 7

Complementary Base Pairing

Answer 7

Used to describe how the bases A always bond with T, and C with G

Question 8

Continuous Variation

Answer 8

Variation that shows a range e.g skin colour / gradual changes e.g height and weight

Question 9

Diploid

Answer 9

Cell with the full complement of chromosomes (46 in humans)

Question 10

Discontinuous Variation

Answer 10

Variation that is ‘either/or’ e.g blood groups, ability to roll tongue or not

Question 11

DNA

Answer 11

This is the chemical which carries genetic information in the nuclei of cells, made up of phosphate units, sugar units and 4 types of bases.

Question 12

Dominant

Answer 12

This is the allele which will be ‘expressed’ in the phenotype if it is present as either a single gene or as two genes e.g B

Question 13

Double Helix

Answer 13

Name given to the twisted ladder shape of the DNA

Question 14

Fertilisation

Answer 14

Male sex cell (gamete) combines with a female sex cell (gamete) to form a zygote

Question 15

Gamete

Answer 15

A sex cell i.e sperm or egg (ovum) in animals. Ovum and pollen in plants

Question 16

Gene

Answer 16

Piece of DNA which codes for a particular protein and therefore a characteristic e.g tongue rolling

Question 17

Genetic Variation

Answer 17

Differences in (DNA / genes / alleles), differences within a species

Question 18

Genotype

Answer 18

The combination of alleles for each trait e.g BB, Bb or bb

Question 19

Haploid

Answer 19

Cell with half the full complement of chromosomes (23 in humans)

Question 20

Heterozygous

Answer 20

This means having a dominant and recessive allele e.g Bb

Question 21

Homozygous

Answer 21

A pair of alleles that are the same e.g HH or hh

Question 22

Hydrogen Bonds

Answer 22

Attractive forces that hold the two strands of DNA together

Question 23

Inheritable

Answer 23

The information can be passed down on to the offspring. It must affect the genetic information in the gametes

Question 24

Karyotype

Answer 24

A photograph or diagram of the chromosomes of a cell arranged in an orderly fashion

Question 25

Meiosis

Answer 25

Cell division that reduces the number of chromosomes to half the normal number, producing 4 genetically different cells. This is what happens in the testes and ovary; meiosis produces gametes

Question 26

Mitosis

Answer 26

This is a genetically exact division of a cell- produces 2 identical daughter cells

Question 27

Mono hybrid Cross

Answer 27

A straightfoward cross involving only one pair of genes or alleles

Question 28

Mutation

Answer 28

This is a sudden, permanent change in a gene or whole chromosome, a mutation is a change in the order of DNA bases that causes a new allele

Question 29

Natural Selection

Answer 29

Organisms with characteristics best suited to their environment become more successful, and so expand in numbers

Question 30

Non Inheritable

Answer 30

The information can be passed on to the offspring as it is due to a change in the somatic cells, due to environment. (Affects only the organism, not the offspring.)

Question 31

Nucleotide

Answer 31

A unit built up of a base, a sugar and a phosphate group

Question 32

Pedigree Chart

Answer 32

A family tree drawn with standard genetic symbols, showing inheritance patterns for specific characteristics e.g straight or curly hair

Question 33

Phenotype Ratio

Answer 33

Ratio of phenotype’s e.g 3 brown hair : 1 blonde hair (a prediction of the phenotype’s and their occurrence as a result of a cross.)

Question 34

Phenotype

Answer 34

The expression of a genotype; this is what you look like e.g brown or blue eyes

Question 35

Phosphate

Answer 35

Group that alternates with the ribose sugar in the DNA backbone

Question 36

Punnett Square

Answer 36

Name given to the grid of squares that may be drawn to show the range of combinations of genes that may occur

Question 37

Pure Breeding

Answer 37

A group of identical individuals that always produce offspring of the same phenotype when interbred, they are homozygous individuals e.g BB or bb

Question 38

Recessive

Answer 38

This is the allele which is only expressed if there are two such alleles e.g b

Question 39

Reduction Division

Answer 39

Another name for meiosis

Question 40

Ribose

Answer 40

A sugar group that alternates with the phosphate group in the DNA backbone

Question 41

Semi Conservative

Answer 41

Each double stranded DNA molecule is composed of one parental strand and one newly male strand

Question 42

Sexual Reproduction

Answer 42

Reproduction involving two parents, where the offspring has some features inherited from each

Question 43

Somatic

Answer 43

Somatic cells are body cells

Question 44

Symbols

Answer 44

Use of capital letter for the dominant gene and the same small letter for the recessive e.g R for round pea and r for wrinkled pea, where round (R) is dominant

Question 45

Template

Answer 45

Pattern

Question 46

Trait

Answer 46

Another word for characteristics e.g brown hair

Question 47

Triplet Code

Answer 47

Genetic code made by sequences of three bases in the DNA e.g AAA, GCT, CAT etc

Question 48

Variation

Answer 48

The differences among parents and their offspring or among individuals in a population

Question 49

Zygote

Answer 49

Cell formed when a sperm cell fuses with an egg cell